Thanks to Daniel Tammet - a Duh and Aha Moment at the Same Time

What is 64 x 75? He asks in his TED talk and I actually do the X (Duh) -- 64 is 8 x 8, 75 is 15 x 5, so I can do 8 x 15 easily - 120, and then 8 x 120 is easy - 960 and then 5 x 960 - well, it's easier to do 5 x 1000 and then subtract 5 x 40 ... so I get 4800 and I think - really - a nice round # like that? And then, ... duh - why did I do the X in the first place? What is 75? 75% is 3/4 - if you think that way, you get 4800 in the blink of an i. Duh/Aha.